Butylhydroxyoxostannane

Endpoint summary

Description of key information

Hydrolysis

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical Butylstannonic acid can be expected to be range from  > 5 to 40 days, respectively. Thus, based on this, test chemical Butylstannonic acid is considered to be not hydrolysable in water.

Additional information

Hydrolysis

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the half-life of the test chemical Butylstannonic acid.The studies are as mentioned below:

The half-life of the test chemical was determined at different pH range. The study was performed according toOECD Guideline 111 (Hydrolysis as a Function of pH) at a temperature of 50°C. Initial test substance concentration used for the study was 106.3 mg/l. Stock solutions containing approximately 10 mg test substance/10 ml methanol were made. 100 µl of the stock solution was added to a vial. Subsequently, 10.0 ml of sterilized buffer solution pH 4.0, 7.0, or pH 9.0, or 10.0 ml of sterilized Milli-Q water was added to the vial. Each vial was closed with a crimpcap closure. The vials were kept at 50°C for 5 days. Quality Control (QC) samples were prepared in duplicate on each day of analysis of the hydrolysis solutions, by adding a stock solution of the substance in methanol to 12.5 ml Milli-Q water. The concentration of the QC samples was approximately 80 mg/l, which corresponds to the initial concentration of the hydrolysis solutions (i.e., 106.3 mg/l in 10.0 ml, diluted to 12.5 ml during the derivatization and extraction procedure). To each QC sample, an aliquot of internal standard solution (monoheptyltin trichloride, diheptyltin dichloride, tripropyltin chloride, and tetrapropyltin in methanol) was added and each sample was derivatized with STEB, extracted and analyzed using GC-MS. The concentration of the test substance was determined at t = 0 and t = 5 days, plus one intermediate point in time, t = 1 day. For each pH, the percent hydrolysis after 5 days was calculated from the test substance concentrations measured at t = 0 and t = 5 days. The sterility tests performed at the end of the hydrolysis tests did not show any bacterial activity. Biodegradation of the test substance in the hydrolysis solutions did not occur. The percentage hydrolysis was calculated as: [(mean concentration (mg/l) at t = 5 days - mean concentration (mg/l) at t = 0) / (mean concentration (mg/l) at t = 0)] * 100%. The percentage hydrolysis of the test substance (analyzed after derivatization with STEB to the corresponding tetra-alkylated compound) was less than 10% after incubation in buffer solution of pH 4.0 and in Milli-Q water at 50°C for 5 days. Therefore, test chemical is considered hydrolytically stable at pH 4.0 and in Milli-Q water. In buffer solutions pH 7.0 and pH 9.0, the relative difference between the substance concentrations measured after incubation at 50°C for 5 days and at t = 0 was more than 10% (+52% in buffer solution pH 7.0 and -37% in buffer solution pH 9.0). The percentage recovery of the test chemical after 5 days was determined to be 99.0, 82 and 107% at pH 4, 7 and 9, respectively. As no hydrolysis of test chemical was observed for a period of 5 days,the half-lives was determined to be > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C, respectively. Based on the half-life values, it is concluded that test chemical is not hydrolysable.

In an another hydrolysis study, the neutral hydrolysis half-life value of test chemical was determined to be ranges from 20-40 days, respectively. Based on the half-life values, it is concluded that test chemical is not hydrolysable.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical Butylstannonic acid can be expected to be range from  > 5 to 40 days, respectively. Thus, based on this, test chemical Butylstannonic acid is considered to be not hydrolysable in water.